Adam: Heheheh, Fred . . . soil you self!
You blink rapidly in shock! Shocked at being as small as an action figure . . . shocked that your now towering baby brother was speaking so clearly . . . and extra shocked at what he just said.
Adam: you now da littlest bwother! So you gots ta do what I say! And I want you to mess yourself! If you don't . . .
He grins devilishly as he pats his stretching, brown/yellow, squishing diaper.
You cringe as you can only imagine what a giant mischievous baby might do to punish him . . . but you also have your pride as the eldest of your siblings . . .
Adam grows a little impatient and slams his pudgy little fist down on the carpeted floor just a few inches/feet from you!